In a typical percussion-type primer, the primer cup is constructed as a one-piece integral arrangement, which is flexed and distorted when engaged by a firing pin. The primer cup remains completely intact and provides obturation when the ammunition is fired. In a typical electric-type primer, the primer cup must consist of more than one integral piece, so that an insulator separates the outer housing of the primer, which is at ground potential, from the primer button which will be at the firing voltage when the electric firing switch or trigger is actuated. Since the primer cup for an electric primer is made of two or three parts, it cannot be operated in an impact percussion mode, since indentation of the button will deform it, and this can destroy the seal between the various parts of the primer cup. Accordingly, heretofore, there has not been a successful design which can accommodate the requirements and features of both a percussion-type primer and an electric-type primer.
In addition, certain gun systems are more compatible with electric primed ammunition, while other gun systems are more compatible with percussion-initiated ammunition. Therefore, the same munition, if primed with a dual electric-percussion primer, could be used in both types of gun systems, whereas under present circumstances, separate munitions would have to be kept in inventory for each of the different types of gun systems. Furthermore, under present circumstances, there is always a danger that ammunition of the same configuration with percussion primers would inadvertently be supplied to gun systems that are electrically fired and result in malfunctions. For example, one Navy 20 MM cartridge (M9782) is identical to another 20 MM cartridge (M210), except that the former is primed with an electric primer, whereas the latter is primed with a percussion primer. Accordingly, the possibility of one being inadvertently used instead of the other is a potential danger. It is therefore recognized that the availability of a combination percussion-electric primer that is fully functional as an electric primer or a percussion primer would offer opportunities for developing munitions with a higher amount of interchangeability. In addition, such a combination-type primer would advance the commonality thrust and would eliminate certain logistic problems.
Broadly, it is an object of the present invention to provide an improved primer which overcomes one or more of the aforesaid drawbacks. Specifically, it is within the contemplation of the present invention to provide a combination percussion-electric primer which can be operated as either a percussion primer or an electric primer, and which involves fewer parts and is easier to manufacture than previous primers.
It is a further object of the present invention to provide a combination percussion-electric primer wherein the contact button will not be distorted, and the pressure developed in the cartridge will be utilized to push the primer parts more tightly together and provide an improved sealing arrangement.
It is a still further object of the present invention to provide a combination percussion-electric primer which can be used in gun systems which are electrically primed, or which are percussion primed, and thereby avoid the need for separate munition inventories.
It is a still further object of the present invention to provide a combination percussion-electric primer which eliminates the danger that an electric primer could be inadvertently placed in a percussion-type cartridge, or vice versa.